1350kv...Why did I buy this?

[redshift]

Was looking at the link for your packs, seems Tower has put out some bad info.

"NEVER allow to Discharge below 2.5V per cell"

NO. The absolute minimum is 2.8V, and the widely used cutoff is 3.0, for a buffer zone.

Many people (myself included) use 3.2V per cell for cutoff, usually anything below that you will notice the power drop off.

I am using Hyperion Swift Classic 4000 2S 20C packs, which are very similar to the first set of Orions you linked. You'll get 15-18 minutes in a proper setup. Maybe use that for reference until you get a feel for things. The 3800 hardcase packs will be good for 12-15 probably, but will be stronger.

You can charge the 4000's and the 3800's at 4 amps for a 1C charge rate, technically you would charge the 3800's at 3.8 amps, but 4 is close enough. And just so you know I have been charging my Hyperions at 8 amps (2C) for about 9 months now, they take it just fine. Incredibly good packs, nothing but praise for 'em!

[Havoc]

Okay, so, the 1350kv can move on 14 nimh cells. It appears that only two of my Trinity batteries are good. I decided to charge both on that Checkpoint charger paying close attention to the discharge and recharge. Both stopped charging at around 2000mah, so I forced them to start again, both were very warm at the completion. With some time to cool, I prepped the Emaxx, had to resolder one of the connections on the ESC.

Anyway, slapped em in, walked outside and WTF!?!? I was riding wheelies, couldn't do a standing backflip, BUT, could get one in a few feet. It was like a different truck. The 1350kv can push this thing just fine, and the temps were great:

motor can = 115 - 125f
esc heatsink = 110 - 115f (fan kicked on once for a few seconds)
batteries = 115 - 128f

I was worried about the possibility of a bad rotor, but it looks like on each test run, one or both of the packs had bad charges due to out of sync cells.

Well, now I have a spare 2250kv I guess, there is no point is switching this out. However, I am considering a complete resolder job with better solder and using 6mm connectors instead of 4mm for the motor connection.

So, it was my crappy batteries, but the right combination of the two least crappiest yielded a good run (finally). I know, I know, ditch the nimh and get the lipos going. I will.

Need to make a few more test runs to make sure everything is solid. I got about 10-12 minutes out on that run, could have been longer except for the newly grown grass from all the stupid rain. Deep grass = power drain...

[Havoc]

One other quick question. Am I destroying these nimh batteries by using them with this RX8 1350kv combo? I would think the higher kv motors would cause more wear, but I read different stuff all over the place.

[emaxxnitro]

Originally Posted by Havoc

One other quick question. Am I destroying these nimh batteries by using them with this RX8 1350kv combo? I would think the higher kv motors would cause more wear, but I read different stuff all over the place.

the lower kv will be easier on nimh but they will fry quick. need lipos imo